Ontogeny of the larynx and flight ability in Jamaican fruit bats (Phyllostomidae) with considerations for the evolution of echolocation.

Echolocating bats have adaptations of the larynx such as hypertrophied intrinsic musculature and calcified or ossified cartilages to support sonar emission. We examined growth and development of the larynx relative to developing flight ability in Jamaican fruit bats to assess how changes in sonar production are coordinated with the onset of flight during ontogeny as a window for understanding the evolutionary relationships between these systems. In addition, we compare the extent of laryngeal calcification in an echolocating shrew species (Sorex vagrans) and the house mouse (Mus musculus), to assess what laryngeal chiropteran adaptations are associated with flight versus echolocation. Individuals were categorized into one of five developmental flight stages (flop, flutter, flap, flight, and adult) determined by drop-tests. Larynges were cleared and stained with alcian blue and alizarin red, or sectioned and stained with hematoxylin and eosin. Our results showed calcification of the cricoid cartilage in bats, represented during the flap stage and this increased significantly in individuals at the flight stage. Thyroid and arytenoid cartilages showed no evidence of calcification and neither cricoid nor thyroid showed significant increases in rate of growth relative to the larynx as a whole. The physiological cross-sectional area of the cricothyroid muscles increased significantly at the flap stage. Shrew larynges showed signs of calcification along the margins of the cricoid and thyroid cartilages, while the mouse larynx did not. These data suggest the larynx of echolocating bats becomes stronger and sturdier in tandem with flight development, indicating possible developmental integration between flight and echolocation.

Short- and long-term effects of a neonatal low-protein diet in rats on the morphology of the larynx.

OBJECTIVE: The aim of this study was to investigate the short- and long-term effects of a maternal low-protein diet during lactation on offspring laryngeal morphology. Our hypothesis was that a neonatal low-protein diet during the critical period of development alters micro- and macroscopic structures of the larynx in adult rats. METHODS: Male Wistar rats were assigned to a control (casein 17%, n=24) or low-protein (casein 8%, n=24) group according to their mother's diet during lactation. Body weight gain and growth rate were recorded throughout the experiment. The larynx was removed from offspring at days 22 and 60 of life. The anteroposterior and laterolateral lengths of the cartilages epiglottis, thyroid, and cricoid were measured by a digital caliper. The supraglottis, glottis, infraglottis, and vocal cords were stained by hematoxylin-eosin and their structures were analyzed by a Scion Image Beta 4.0.2 program. RESULTS: Pups from mothers fed a low-protein diet showed a lower body weight gain. The laterolateral and anteroposterior lengths of the larynx were shorter in undernourished offspring at 22 d old. There were no differences in the structure of the supraglottis, glottis, and infraglottis between groups except for keratinization in pups from undernourished mothers. The microstructure of the vocal cords was changed only at 60 d old. CONCLUSION: Macroscopic structures of the larynx are sensitive to short-term effects of a neonatal low-protein diet. Vocal cord development can be studied within the context of programming because their microscopic structures are sensitive to the long-term effects of a low-protein diet during lactation.

Patologías vocales en niños / Vocal pathology in children

El presente artículo muestra una introduccion con referencia a la embriología y desarrollo de la laringe. Se puntualizan cuáles son las patologías más frecuentes a nivel laríngeo en el recién nacido y lactante dando algunas pautas clínicas de cada una de estas enfermedades. Así mismo se mencionan las patologías vocales más frecuentes en el niño pre-escolar y escolar dándose sugerencias de tratamientos médico-quirúrgicos.También se hacen mención de la muda vocal que se realiza en la etapa de la pubertad.

The following article consists in an introduction about embryology and larynx growth. It explain about pathologies wich are most frequent at the laryngeal level in newborn child and milkfed baby, offering some clinical guides for each of these diseases. Likewise the most persistent vocal pathologyes are explained during pre-scholar and students periods, suggesting medical and surgical treatments. Finally this research explins about vocal mute showed in the puberty stage.

Posterior cricoidotomy lumen augmentation for treatment of subglottic stenosis in children.

OBJECTIVES: To determine the results of posterior cricoidotomy lumen augmentation in the treatment of moderate and severe subglottic stenosis in children, and to assess the effect of this surgery on the growth of the larynx in young children. DESIGN: A 17-year retrospective study. PATIENTS AND METHODS: Thirteen children with moderate and severe subglottic stenosis who underwent posterior cricoidotomy lumen augmentation from 1980 to 1996. Eight children (62%) were male and 5 (38%) were female. The average age was 4.7 years (age range, 8 months to 15 years). Six (46%) of the 13 children were younger than 3 years. Nine children (69%) had acquired subglottic stenosis, 3 of whom had a combined subglottic-posterior glottic stenosis, and 4 (31%) had congenital subglottic stenosis. All the children already had a tracheotomy tube placed and had undergone treatment at our clinic or at other institutions. The surgical procedure we used included a cricoid lamina split with grafting (2 children with costal cartilage graft and 11 with buccal mucosal graft) and stenting. RESULTS: Twelve (92%) of the 13 children underwent decannulation, and 1 (8%) is still undergoing treatment: decannulation is expected to be carried out in the near future. Of the 12 children who underwent decannulation, 9 demonstrated good postoperative voice quality and 3, who had combined subglottic-posterior glottic stenosis, developed impaired voice function. Following stent removal, all children experienced some degree of difficulty in swallowing saliva and liquids, which was soon overcome. No evidence of surgery-induced laryngeal growth impairment in younger children was observed. CONCLUSIONS: The posterior cricoidotomy lumen augmentation is a safe and effective technique for the treatment of moderate and severe subglottic stenosis in children of any age. This study lends further support to the assertion that external surgery does not affect the growth of the larynx in younger children.